VM ids for ESX host and VCenter

Hi All,

Let's say we have a virtial machine VM1  with a certain vmid (moid).

If this host is managed by VCenter and we are accessing the same VM  via VCenter it will get different vmid. is there any way to relate those 2 vmids?

Can we query ESX host to know the VMid on vcenter or opposite? How about VMs that has been relocated to different host. How the moved VM can  be identified? It looks like its id will not be preserved. VM names are not a reliable way of identifying VMs as VMs can be renamed. Is there any global vm identifier that stays the same regardess of the VM movemets or access method?

Thanks a lot